Question

A soap bubble is given a negative charge, then its radius :

• A. Increases
• B. Decreases
• C. Remains unchanged
• D. None of these

Answer 1

The correct option is A

Increases

Explanation for the correct option

Option (A)

1. We know a soap bubble is a conductor, according to the question it has a negative charge. By the spherical symmetry of the bubble, the total amount charged will be distributed uniformly over the bubble's surface.
2. As we know same charges repulse each other. So due to the mutual repulsion between charges placed on the bubble surface, the size of the bubble will increase. That's why the radius of the bubble will Increase.

∙ Diagram

Explanation for the incorrect options

1. Due to negative charge on the bubble surface, the radius of the bubble will be increased.
2. Bubble is conductor, after giving some same charge it will remains unchanged, it is unscientific.
3. So, options (D), (B) and (C) are incorrect.

Therefore, option (A) is correct